The Islamic world isn't totally quiet. There have been protests against terrorism and in remembrance of the children. On the other hand, the Islamic nations are not willing to qualify the genocide in Sudan as a genocide. They never are when their people are perpetrating it.
Those deaths do cry out for justice. I just want to make the point that they have children too, and killing a bunch of them is not the solution. For years, the Russians have been killing their children, not on purpose but in the context of fighting the Chechens, so they think they are justified to shoot babies in the back. We should assassinate the terrorists responsible, with as little "collateral" damage as possible.
You are correct. And in conventional warfare that is done. But you can't stop collateral damage in warfare. You can only do your best to minimalize it. Still, it must be done.